Method and apparatus for multi-algorithm detection

ABSTRACT

Embodiments of the present invention provide a method, apparatus and system for detecting a transmitted signal according to a detection algorithm selected from two or more detection algorithms based on a predetermined selection criterion.

BACKGROUND OF THE INVENTION

A wireless communication device may include a receiver to receive atransmitted signal traveling through a wireless communication channel.The receiver may include a detector to detect symbols of the transmittedsignal. The transmitted signal may be affected, e.g., distorted orcorrupted, by various types of interference while traveling through thechannel. Types of interference may include, for example, white noise,Adjacent-Channel Interference (ACI) or Co-Channel Interference (CCI).

There are detectors using pre-defined detection algorithms intended toimprove performance in an environment characterized by white noiseinterference.

There are also detectors of multiple-antenna receivers using pre-defineddetection algorithms intended to improve performance in an environmentcharacterized by CCI.

Detectors using pre-defined detection algorithms may provide sub-optimalresults in a dynamically changing environment, e.g., due to movement ofa user of the device implementing the algorithm or movement of otherusers. A relatively small change in the environment, e.g., from anenvironment characterized by CCI to an environment characterized bywhite noise interference, may significantly affect the efficiency of thedetector since the pre-defined detection algorithm may be sensitive to aparticular interference type.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter regarded as the invention is particularly pointed outand distinctly claimed in the concluding portion of the specification.The invention, however, both as to organization and method of operation,together with features and advantages thereof, may best be understood byreference to the following detailed description when read with theaccompanied drawings in which:

FIG. 1 is a simplified block diagram of a communication system inaccordance with some exemplary embodiments of the present invention;

FIG. 2 is a schematic block diagram of a multi-algorithm detectoraccording to some exemplary embodiments of the invention;

FIG. 3 is a simplified, conceptual block diagram of a calculating devicein accordance with some exemplary embodiments of the present invention;

FIG. 4 is a schematic flow-chart illustration of a multi-algorithmdetection method, according to some exemplary embodiments of theinvention;

FIG. 5 is a schematic block diagram of a dual-algorithm detectoraccording to some exemplary embodiments of the invention; and

FIG. 6 is a schematic flow-chart of a dual-algorithm detection methodaccording to some exemplary embodiments of the invention.

It will be appreciated that for simplicity and clarity of illustration,elements shown in the figures have not necessarily been drawn to scale.For example, the dimensions of some of the elements may be exaggeratedrelative to other elements for clarity. Further, where consideredappropriate, reference numerals may be repeated among the figures toindicate corresponding or analogous elements.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description, numerous specific details are setforth in order to provide a thorough understanding of the invention.However it will be understood by those of ordinary skill in the art thatthe present invention may be practiced without these specific details.In other instances, well-known methods, procedures, components andcircuits have not been described in detail so as not to obscure thepresent invention.

Some portions of the detailed description that follows are presented interms of algorithms and symbolic representations of operations on databits or binary digital signals within a computer memory. Thesealgorithmic descriptions and representations may be the techniques usedby those skilled in the data processing arts to convey the substance oftheir work to others skilled in the art.

Unless specifically stated otherwise, as apparent from the followingdiscussions, it is appreciated that throughout the specificationdiscussions utilizing terms such as “processing,” “computing,”“calculating,” “determining,” or the like, refer to the action and/orprocesses of a computer or computing system, or similar electroniccomputing device, that manipulate and/or transform data represented asphysical, such as electronic, quantities within the computing system'sregisters and/or memories into other data similarly represented asphysical quantities within the computing system's memories, registers orother such information storage, transmission or display devices.

It should be understood that embodiments of the present invention may beused in a variety of applications. Although the scope of the presentinvention is not limited in this respect, the circuits and techniquesdisclosed herein may be used in many apparatuses such as receivers of aradio system. Receivers intended to be included within the scope of thepresent invention include, by a way of example only, cellularradiotelephone receivers, spread spectrum receivers, digital systemreceivers and the like.

Types of cellular radiotelephone receivers intended to be within thescope of the present invention include, although not limited to, CodeDivision Multiple Access (CDMA), CDMA 2000 and wideband CDMA (WCDMA)cellular radiotelephone, receivers for receiving spread spectrumsignals, and the like.

Devices, systems and methods incorporating aspects of embodiments of theinvention are also suitable for computer communication networkapplications, for example, intranet and Internet applications.Embodiments of the invention may be implemented in conjunction withhardware and/or software adapted to interact with a computercommunication network, for example, a local area network (LAN), widearea network (WAN), or a global communication network, for example, theInternet.

Reference is made to FIG. 1, which schematically illustrates anexemplary communication system in accordance with some embodiments ofthe present invention, enabling a first communication device 100 tocommunicate with a second communication device 102 over a communicationchannel 104.

Although the scope of the present invention is not limited in thisrespect, communication devices 100, 102 may include wireless modems ofcomputers and communication channel 104 may be part of a WAN or a LAN.For example, the system may be a wireless LAN (WLAN) system.Alternatively, although the scope of the present invention is notlimited in this respect, the communication system shown in FIG. 1 may bepart of a cellular communication system, with one of communicationdevices 100, 102 being a base station and the other a mobile station orwith both communication devices 100, 102 being mobile stations, a pagercommunication system, a personal digital assistant (PDA) and a server,etc. In such cases, although the scope of the present invention is in noway limited in this respect, communication device 100 may include aRadio Frequency (RF) antenna 101, and communication device 102 mayinclude an array of m RF antennas 111, as is known in the art. Althoughthe scope of the present invention is not limited in this respect, typesof antennas that may be used for antenna 101 and/or antennas 111 mayinclude but are not limited to internal antenna, dipole antenna,omni-directional antenna, a monopole antenna, an end fed antenna, acircularly polarized antenna, a micro-strip antenna, a diversity antennaand the like. In the case of a cellular wireless communication system,according to some embodiments of the invention, the communication systemshown in FIG. 1 may be a 3^(rd) Generation Partnership Project (3GPP),such as, for example, Frequency Domain Duplexing (FDD), Global Systemfor Mobile communications (GSM), Wideband Code Division Multiple Access(WCDMA) cellular system and the like.

Communication device 100 may include a transmitter 106 to transmit asignal, as is known in the art. Communication device 102 may include areceiver 120, which may include a multi-algorithm detector 130, asdescribed in detail below. Receiver 120 may also include an array of mRF to Base-Band (BB) converters 115 to convert RF signals received byantennas 111 into m BB signals 208, as is known in the art.

In some embodiments, receiver 120 and transmitter 106 may beimplemented, for example, using separate and/or integrated units, forexample, using a transmitter-receiver or a transceiver.

FIG. 2 schematically illustrates a block diagram of a multi-algorithmdetector 200 according to some exemplary embodiments of the invention.

According to some embodiments of the invention, detector 200 may beadapted to detect the transmitted signal according to a detectionalgorithm selected out of two or more detection algorithms based on apre-selected criterion, as described below.

According to some embodiments of the invention, detector 200 may receivem input signals 208. Detector 200 may include an array 204 of nsub-detectors 205, wherein n is at least two, and wherein n may be equalto or different than m. Sub-detectors 205 may have inputs associatedwith at least some of the m signals 208. At least some of sub-detectors205 may be able, when activated, to detect the transmitted signal, andto provide an output signal 213 including a representation of thedetected signal according to a pre-selected detection algorithm, asdescribed below. The pre-selected detection algorithm may include anydetection algorithm as is known in the art, for example, a Minimum MeanSquare Error (MMSE) algorithm or a Maximal Likelihood SequenceEstimation (MLSE) algorithm, e.g., for example, the algorithm describedin US Patent Application 20030123583 to Yellin Daniel et al. Outputsignals 213 of sub detectors 205 may be provided to a controller 202.

According to some embodiments of the invention, controller 202 may beadapted to control an output 210 of detector 200 according topre-selected criteria, as described below. Controller 202 may receiveinputs corresponding to at least some of m input signals 208. Controllermay also receive inputs corresponding to one or more of n detectedsignals 213 from sub-detectors 205. In some embodiments, controller 202may include a calculator 230 to calculate a value, i.e., a QualityMetric (QM), e.g., a Signal to Noise Ration (SNR), a Log LikelihoodRation (LLR), or a Mean Square Error (MSE), corresponding to signals 208and signals 213, as described below. Controller 202 may also include amemory unit 231 to store at least some of the values calculated bycalculator 230. Controller 202 may further include a max-detector 232 todetect the highest of two or more values, as described below.Max-detector 232 may include any maximum detection algorithm, as isknown in the art. Controller 202 may further include a control unit 234able to control activation of at least some of sub-detectors 205, asdescribed below. Control unit 234 may also control the operation of aselector 206, e.g., by a control signal 216, to connect the output of aselected sub-detector 205 to output 210, as described below. Selector206 may include any circuitry and/or software to connect the output ofthe selected sub-detector to output 210. For, example, selector 206 mayinclude a switching device, as is known in the art.

According to some embodiments of the invention, controller 202 may beable to control activation of one or more of sub-detectors 205 using oneor more, respective, control signals 214.

According to some embodiments of the invention, controller 202 mayactivate one or more of sub-detectors 205 substantially simultaneously,for example, when controller 202 operates in a “performance” mode ofoperation, as described in detail below.

According to other embodiments of the invention, controller 202 mayactivate one or more of sub-detectors 205 sequentially, for example,when controller 202 operates in a “power” mode of operation, asdescribed in detail below.

Reference is also made to FIG. 3, which conceptually illustrates acalculating device or unit 300 to perform functions in accordance withsome exemplary embodiments of the present invention.

According to some exemplary embodiments of the invention, one or more ofcontroller 202, calculator 230, max-detector 232, control unit 234,and/or one or more of sub-detectors 205 may be implemented in a unit ora number of units similar to unit 300, which may include a computingunit 310 and a memory 320 coupled to computing unit 310. Although thescope of the present invention is not limited in this respect, computingunit 310 may include an application specific integrated circuit (ASIC),a reduced instruction set circuit (RISC), a digital signal processor(DSP) or a central processing unit (CPU). The specific type of computingunit 310 and the specific number of units that may be used to implementat least some of the functions described herein may depend on specificimplementations and/or design requirements. Instructions to enablecomputing unit to perform methods according to embodiments of thepresent invention may be stored in memory 320.

A QM, e.g., a SNR, a LLR, a MSE or any other suitable QM, as are knownin the art, may be calculated for a detected signal, denoted y, providedby a sub-detector, e.g., by one of sub-detectors 205. According toembodiments of the invention, the calculated QM may be used forevaluating performance of the sub-detector providing the detectedsignal, for example, a higher calculated QM may indicate higherdetection efficiency. The QM may vary according to detector-relatedcharacteristics, e.g., the detection algorithm used by the sub-detector,and/or according to non-detector related characteristics, e.g.,environment-noise characteristics. The QM may be calculated usingvarious calculation methods, as are known in the art. For example, theQM may be calculated according to a pre-decoding method or apost-decoding method, as are known in the art. For example, the QM maybe calculated according to the following SNR-related equation:$\begin{matrix}{{QM} = {\sum\limits_{i = 1}^{l}\quad{{{{\hat{h}}_{c}(i)}}^{2}/\left( {{\frac{1}{N_{2} - N_{1} + 1}\sum\limits_{j = N_{1}}^{N_{2}}}\quad ❘{{{y(j)} - {{{\hat{h}}_{c}(j)} \otimes {{TSC}(j)}}}❘^{2}}} \right)}}} & (1)\end{matrix}$wherein y(i) denotes the i-th symbol of detected signal y, l denotes thenumber of symbols per signal, ĥ_(c)(i) denotes a channel estimation tapcorresponding to the i-th symbol of y, TSC(j) denotes a j-th symbol of aTraining Sequence Code (TSC), and N₁ and N₂ denote first and lastindices of the TSC, respectively, as are known in the art. For example,N1 and N2 may be 1 and 26, respectively, if a pre-decoding method isused, and N1 and N2 may be 1 and 148, respectively, if a post-decodingmethod is used.

Reference is also made to FIG. 4, which schematically illustrates a flowchart of a multi-algorithm detection method, which may be implemented bya multi-algorithm detector, e.g., detector 200, according to someexemplary embodiments of the invention.

According to exemplary embodiments of the invention, the method mayinclude selecting a mode of operation, e.g., a “performance” mode ofoperation or a “power” mode of operation, as indicated at block 402.According to some embodiments of the invention, if the performance modeis selected, a criterion for selecting the detection algorithm mayrelate to a highest, e.g., a maximal, quality value, e.g., QM, asdescribed below. If the power mode is selected, the criterion forselecting the detection algorithm may relate to a pre-selected minimumquality value, e.g., QM, as described below. According to someembodiments, the modes of operation may be selected manually, e.g., by auser. According to other embodiments, the mode of operation may beselected automatically, e.g., by controller 202. For example, controlunit 234 may be able to select between the two modes of operationaccording to an energy level of a power source, e.g., a battery, used tosupply detector 200 with electric energy.

If the performance mode of operation is selected at block 402, at leastsome of sub-detectors 205 may be activated substantially simultaneously,as indicated at block 418. For example, control unit 234 may activate,e.g., by signals 214, at least some of sub-detectors 205.

As indicated at block 420, according to some embodiments of theinvention, a QM corresponding to the outputs of activated sub-detectors205 may be calculated, e.g., by calculator 230, for example, usingEquation 1. The QMs calculated by calculator 230 may be stored in memory231.

As indicated at block 422, a highest QM of the calculated QMs may bedetected, e.g., by max-detector 232, and a sub-detector corresponding tothe highest QM may be selected, e.g., by control unit 234.

As indicated at block 424, the output of the detector may be connectedto an output of the selected sub-detector. For example, a selector,e.g., selector 206, may be controlled, e.g., by control signal 216, toconnect output 210 to the output of the selected sub-detector.

If the power mode of operation is selected at block 402, one or more ofthe sub-detectors may be activated sequentially, e.g., by control unit234, according to a predetermined activation sequence. For example, asindicated at block 404, a first sub-detector may be activated accordingto the activation sequence. According to one exemplary embodiment of theinvention, the activation sequence may be predetermined according to anestimated performance value of the sub-detectors, e.g., corresponding topreviously detected signals. According to another exemplary embodimentof the invention, the activation sequence may be predetermined accordingto the robustness level of the sub-detectors, e.g., according to thetype and/or number of environments in which the sub-detector is adaptedto operate.

As indicated at block 406, according to some embodiments of theinvention, a QM corresponding to the output of the active sub-detectormay be calculated, e.g., by calculator 230, for example, using Equation1.

As indicated at block 408, the QM of the active sub-detector may becompared, e.g., by control unit 234, with a preset minimum-qualityvalue. The minimum-quality value may be preset according to specificimplementations. For example, in a GSM network a minimum-quality valueof 100, e.g., corresponding to a 20 dB SNR, may be implemented.

If the QM corresponding to the active sub-detector is equal to or higherthan the minimum-quality value, the active sub-detector may be selected,e.g., by controller 202, as indicated at block 410. The output of thedetector may be associated with an output of the selected sub-detector,as described above (block 424).

As indicated at block 412, if the QM corresponding to the activesub-detector is lower than the minimum-quality value, the QM may bestored in a memory, e.g., memory 231. The method may include determiningwhether a currently activated sub-detector is the last sub-detector,i.e. if a QM has been calculated for all the other sub-detectors. Thismay be accomplished, for example, by implementing a counter (not shown),as is known in the art, to count the number of QM calculationsperformed. According to this example, control unit 234 may determinethat the currently activated sub detector is the last sub-detector to beactivated in the predetermined sequence when a value of the counterequals the number of sub-detectors 205 in array 204.

If the currently activated sub-detector is determined to be the lastsub-detector to be activated in the predetermined sequence, a highest QMof the calculated QMs stored in the memory may be detected, e.g., bymax-detector 232. The sub-detector corresponding to the maximal QM maybe selected, e.g., by control unit 234, as indicated at block 422. Thus,according to some embodiments, the QM corresponding to the selectedsub-detector in the power mode of operation may be lower than theminimum-quality value, but higher than the QM corresponding to the othersub-detectors 205 in array 204.

As indicated at block 416, if the currently activated sub-detector isdetermined not to be the last sub-detector, the active sub-detector maystore at least some values, e.g., y(i) and/or ĥ_(c)(i), calculated bythe active sub-detector, the active sub-detector may be de-activated,e.g., by control unit 234, and the next sub-detector 205 according tothe activation sequence may be activated, e.g., by control unit 234. TheQM corresponding to the newly activated detector may be calculated,e.g., by calculator 230, as described above (block 406).

Reference is made to FIG. 5, which schematically illustrates a blockdiagram of a dual-algorithm detector 500 according to some exemplaryembodiments of the invention.

According to some exemplary embodiments of the invention, detector 500may receive a first input signal 518 from a first RF to BB converter517, and a second input signal 519 from a second RF to BB converter 520.Detector 500 may include a Dual Input Single Output (DISO) MLSE detector504, a DISO MMSE detector 506, and a DISO selector 508, as are known inthe art. MLSE detector 504 may be efficient for an environmentcharacterized by white noise, and MMSE detector 506 may be efficient foran environment characterized by an interference created predominantly byone or more interferers. Detector 500 may also include a controller 502to control an output 524 of detector 500 according to predeterminedcriteria, as described below.

Controller 502 may include a calculator 530 to calculate a QMcorresponding to an output of detector 504 or an output of detector 506.For example, calculator 534 may implement Equation 1 to calculate theQM. Controller 502 may also include a memory unit 531 to store at leastsome values calculated by calculator 230. Controller 502 may furtherinclude a max-detector 532, e.g., as described above. Detector 502 mayfurther include a control unit 534 able to control activation of atleast one of detectors 504 and 506, as described below. Unit 534 mayalso control selector 506, e.g., by a control signal 510, to connectoutput 524 to an output of one of detectors 504 and 506, as describedbelow.

Reference is also made to FIG. 6, which schematically illustrates a flowchart of a dual-algorithm detection method, which may be implemented bydetector 500, according to some exemplary embodiments of the invention.

According to some exemplary embodiments of the invention, a mode ofoperation, e.g., a performance mode of operation or a power mode ofoperation, may be selected, as indicated at block 602. According to someembodiments, the mode of operation may be selected manually, e.g., by auser. According to other embodiments, the mode of operation may beselected automatically, e.g., by control unit 534. For example, controlunit 534 may be able to select between the two modes of operationaccording to an energy level of a power source, e.g., a battery, used tosupply detector 500 with electric energy.

If the performance mode of operation is selected at block 602, controlunit 534 may activate detectors 504 and 506 substantiallysimultaneously, e.g., by sign als 514 and 516, respectively, asindicated at block 618.

As indicated at block 620, according to some embodiments of theinvention, calculator 530 may calculate two QMs corresponding to outputs544 and 546 of detectors 504 and 506, respectively. The QMs calculatedby calculator 530 may be stored in memory 531.

As indicated at block 622, max-detector 532 may detect a highest QM ofthe QMs corresponding to detectors 504 and 506, respectively. Controlunit 534 may select from detectors 504 and 506 the detectorcorresponding to the maximal QM.

As indicated at block 624, control unit 534 may control the operation ofselector 508, e.g., by control signal 510, to connect output 524 to anoutput of the selected detector.

If the power mode of operation is selected at block 602, control unit534 may activate one of detectors 504 and 506, the detector to beactivated may be predetermined, e.g., as described above. For example,detector 504 may be activated, e.g., by signal 514, as indicated atblock 604.

As indicated at block 606, according to some embodiments of theinvention, calculator 530 may calculate a QM, e.g., according toEquation 1, corresponding to the output of the active detector, e.g.,detector 504.

As indicated at block 608, control unit 534 may compare the QM of theactive detector, e.g., detector 504, with a preset minimum-qualityvalue. The minimum-quality value may be preset according to specificimplementations of detector 500, e.g., as described above with referenceto block 408.

If the QM of the active detector, e.g., detector 504, is equal to orhigher than the minimum-quality value, control unit 534 may select theactive detector, e.g., detector 504, as indicated at block 610. Controlunit 534 may control selector 508, e.g., using control signal 510, toassociate output 524 with the output of the selected detector, asindicated at block 624.

As indicated at block 612, if the QM of the active detector, e.g.,detector 504, is lower than the minimum-quality value, control unit 534may store the QM corresponding to the active detector in memory 531.Control unit 534 may also activate the un-active detector, e.g.,detector 506, e.g., by signal 516.

As indicated at block 614, calculator 530 may calculate a QM, e.g.,according to Equation 1, corresponding to the output of detector 506.Max-detector 532 may detect a highest QM of the calculated QMscorresponding to detectors 504 and 506, respectively, as indicated atblock 622.

It will be appreciated by persons skilled in the art that themulti-algorithm detectors described above have a significantly improveddetection ability in a changing environment, compared to the detectionability of prior art detectors under comparable operational conditions.For example, Spatial Interference Cancellation (SIC) detection methods,as are known in the art, may have relatively optimal performance inenvironments characterized by an interference of one dominant interfererarriving from a different location than the signal to be detected.However, SIC methods may have relatively sub-optimal performance inenvironments characterized by an interference of a multiplicity ofinterference sources positioned in different locations. Themulti-algorithm detector, according to embodiments of the invention, mayprovide relatively optimal performance in different environment types,e.g., the environments described above, by utilizing a multiplicity ofmultiple-antenna detection algorithms.

Embodiments of the present invention may be implemented by software, byhardware, or by any combination of software and/or hardware as may besuitable for specific applications or in accordance with specific designrequirements. Embodiments of the present invention may include units andsub-units, which may be separate of each other or combined together, inwhole or in part, and may be implemented using specific, multi-purposeor general processors, or devices as are known in the art. Someembodiments of the present invention may include buffers, registers,storage units and/or memory units, for temporary or long-term storage ofdata and/or in order to facilitate the operation of a specificembodiment.

While certain features of the invention have been illustrated anddescribed herein, many modifications, substitutions, changes, andequivalents may occur to those of ordinary skill in the art. It is,therefore, to be understood that the appended claims are intended tocover all such modifications and changes as fall within the true spiritof the invention.

1. An apparatus comprising: a multi-algorithm detector to detect atransmitted signal according to a detection algorithm selected from twoor more detection algorithms based on a predetermined selectioncriterion.
 2. The apparatus of claim 1 wherein said detector comprisestwo or more sub-detectors able to detect said transmitted signalaccording to said two or more detection algorithms, respectively.
 3. Theapparatus of claim 2 wherein said detector comprises a controller tocontrol the selection of said detection algorithm according to outputsof said sub-detectors.
 4. The apparatus of claim 3 wherein saidcontroller is able to control activation of one or more of said at twoor more sub-detectors.
 5. The apparatus of claim 4 wherein saidcontroller is able to activate at least some of said two or moresub-detectors substantially simultaneously.
 6. The apparatus of claim 4wherein said controller is able to sequentially activate at least someof said two or more sub-detectors according to a preset sequence.
 7. Theapparatus of claim 3 wherein said controller comprises a calculator tocalculate a quality metric corresponding to one or more of saidsub-detectors.
 8. The apparatus of claim 7 wherein said quality metriccomprises a quality metric selected from the group consisting of asignal to noise ratio, a log likelihood ratio, and a mean square error.9. The apparatus of claim 7 wherein said controller comprises amax-detector to detect a highest quality metric of two or more qualitymetrics corresponding to two or more of said sub-detectors,respectively.
 10. The apparatus of claim 1 having a power mode ofoperation, wherein said criterion relates to a preset minimum qualityvalue.
 11. The apparatus of claim 1 having a performance mode ofoperation, wherein said criterion relates to a highest quality metric oftwo or more quality metrics corresponding to said detection algorithms.12. The apparatus of claim 1 wherein one or more of said detectionalgorithms comprises a minimum mean square error algorithm.
 13. Theapparatus of claim 1 wherein one or more of said detection algorithmscomprises a maximal likelihood sequence estimation algorithm.
 14. Awireless communications device comprising: a transceiver able to sendand receive signals; a multi-algorithm detector to detect a transmittedsignal according to a detection algorithm selected from two or moredetection algorithms based on a predetermined selection criterion 15.The device of claim 14 wherein said detector comprises two or moresub-detectors able to detect said transmitted signal according to saidtwo or more detection algorithms, respectively.
 16. The device of claim15 wherein said detector comprises a controller to control the selectionof said detection algorithm according to outputs of said sub-detectors.17. The device of claim 16 wherein said controller comprises acalculator to calculate a quality metric corresponding to one or more ofsaid sub-detectors.
 18. The device of claim 17 wherein said qualitymetric comprises a quality metric selected from the group consisting ofa signal to noise ratio, a log likelihood ratio, and a mean squareerror.
 19. The device of claim 17 wherein said controller comprises amax-detector to detect a highest quality metric of two or more qualitymetrics corresponding to two or more of said sub-detectors,respectively.
 20. The device of claim 14 having a power mode ofoperation, wherein said criterion relates to a preset minimum qualityvalue.
 21. The device of claim 14 having a performance mode ofoperation, wherein said criterion relates to a highest quality metric oftwo or more quality metrics corresponding to said detection algorithms.22. A method comprising: selecting a signal-detection algorithm from twoor more signal-detection algorithms according to a predeterminedcriterion.
 23. The method of claim 22 comprising: calculating two ormore quality metrics corresponding to said two or more signal-detectionalgorithms, respectively; and selecting from the two or moresignal-detection algorithms a signal-detection algorithm correspondingto a highest quality metric of said calculated metrics.
 24. The methodof claim 22 comprising sequentially calculating according to apredetermined sequence a quality metric corresponding to said two ormore signal-detection algorithms, wherein said selected signal-detectionalgorithm corresponds to a calculated quality metric having a valuehigher than a preset minimum-quality value.
 25. An article comprising astorage medium having stored thereon instructions that, when executed bya processing platform, result in: selecting a signal-detection algorithmfrom two or more signal-detection algorithms according to apredetermined criterion.
 26. The article of claim 25 comprising:calculating two or more quality metrics corresponding to said two ormore signal-detection algorithms, respectively; and selecting from thetwo or more signal-detection algorithms a signal-detection algorithmcorresponding to a highest quality metric of said calculated metrics.27. The method of claim 25 comprising sequentially calculating accordingto a predetermined sequence a quality metric corresponding to said twoor more signal-detection algorithms, wherein said selectedsignal-detection algorithm corresponds to a calculated quality metrichaving a value higher than a preset minimum-quality value.
 28. Acommunication system comprising: a first communication device totransmit a signal through a communication channel; and a secondcommunication device to receive said signal, said second communicationdevice comprising a multi-algorithm detector to detect said transmittedsignal according to a detection algorithm selected from two or moredetection algorithms based on a predetermined selection criterion. 29.The system of claim 28 wherein said detector comprises two or moresub-detectors able to detect said transmitted signal according to saidtwo or more detection algorithms, respectively.
 30. The system of claim29 wherein said detector comprises a controller to control the selectionof said detection algorithm according to outputs of said sub-detectors.31. The system of claim 30 wherein said controller is able to controlactivation of one or more of said at two or more sub-detectors.
 32. Thesystem of claim 30 wherein said controller comprises a calculator tocalculate a quality metric corresponding to one or more of saidsub-detectors.
 33. The system of claim 32 wherein said quality metriccomprises a quality metric selected from the group consisting of asignal to noise ratio, a log likelihood ratio, and a mean square error.34. The system of claim 32 wherein said controller comprises amax-detector to detect a highest quality metric of two or more qualitymetrics corresponding to two or more of said sub-detectors,respectively.
 35. The system of claim 28 wherein one or more of saiddetection algorithms comprises a minimum mean square error algorithm.36. The system of claim 28 wherein one or more of said detectionalgorithms comprises a maximal likelihood sequence estimation algorithm.